Underwater vacuum cleaning

Extreme vacuuming - underwater, wearing full dive gear and being nibbled by ducks and penguins...

You think it’s a chore vacuuming the house. Imagine having to vacuum underwater, wearing breathing apparatus and surrounded by inquisitive penguins.

Staff and volunteers at Living Coasts, Torquay’s coastal zoo, use an underwater vacuum cleaner to solve a murky problem. The ingenious device removes sand from the tanks used by penguins and other birds and recycles it back onto their artificial beaches.

Living Coasts spokesperson Phil Knowling explained: “Our system was devised using Sedi-filters, which are normally used by people like the Environment Agency to clear silt from watercourses and rebuild riverbanks. A portable submersible pump with an extendable hose draws sand and water into a large bag that lies on the Living Coasts decking like a beached whale. The sand is caught in the Sedi-filter bag but the water drains out. Because it is under pressure, it spurts out in tiny fountains.”

Water Services Technician, Derek Youd said: “Sand is washed from Penguin Beach during heavy rainfall or comes off the penguins as they clean themselves in the water. This settles at the bottom of the tank. Few other exhibits use just sand, but it is best for the birds that we have a sandy beach, it is as close to their natural habitat as we can get, so this is what we have.”

The unseen and unsung heroes of all this are the zoo volunteers. “They sew up the bags by hand so we can reuse them. The Sedi-filter bags are designed to be filled with silt once and then left on riverbanks like giant sandbags to build them up, as the bag material is fully biodegradable. We want to get the sand out and put it back on the beach, so we have to cut the bags open and sew them back up to reuse them. We can’t put in a zip because the pressure might burst it. The sewing volunteers put in tremendous effort!”

The sand vacuum can be used in the shallows by a keeper in waders or by divers at the bottom of the tank. It has been used twice in 2017 - Derek estimates that they may have moved a total of 32 tonnes of sand on those two occasions.

Derek: “The sand clogs up our water filtration system – it’s a unique problem that needed a unique solution. We also needed something that could be used near the penguins without disturbing them .The pump is very quiet and efficient and they don’t get fussed at all!”

Derek has skilled help: Rob Fox of CMPR is an electrical, mechanical and pump engineer and a professional diver: “Although we undertake many interesting projects, this is one of the more rewarding and enjoyable because I get to dive with penguins! This makes it an inspiring experience, because they are swimming around me as I work.”

Living Coasts is an educational, scientific and conservation charity dedicated to protecting our global wildlife heritage. It is a company limited by guarantee and has an exemption to omit the word ‘Limited’ from its name.